The mod doesn't support 1.0.1, because it was integrated into the release. The only feature that's not there is updating the prices real time. That one, however, was originally not my mod, it's RealTimeFleaMarket from MertCan. We'll discuss where that feature will be updated, in the meantime, you can enjoy selling to flea market in 1.0.1 without the need of this mod.
ohh i see, didn't know selling is integrated in 1.0.1, thanks